STORY HIGHLIGHTS

The death toll is expected to rise, according to hospital sources. There has been no immediate claim of responsibility

A suicide car bomber killed at least 14, including women and children packed into a minibus, at a checkpoint outside a central Iraqi town on Monday morning, police and hospital sources said.

A police officer at the scene said most of the victims died inside their vehicles while waiting to enter Khalis, about 80 km (50 miles) north of Baghdad.

"We still have charred bodies inside many vehicles including a minibus packed with women and children," the police captain said, requesting anonymity.

There was no immediate claim of responsibility, but Islamic State militants have stepped up attacks even as they incur battlefield setbacks in northern and western Iraq.

Hospital sources said the death toll was expected to rise given the extent of critical injuries.

Iraqi Prime Minister Haider al-Abadi has come under pressure to improve security since a suicide attack claimed by Islamic State earlier this month killed 292 in central Baghdad, one of the largest attacks of its kind since the US-led invasion in 2003.

The ultra-hardline militants have lost much of the territory they seized in 2014 and Abadi has pledged to retake this year the northern city of Mosul, the group's de facto capital in Iraq.